When operating storage facilities for order fulfillment several aspects should be taken into account as described below.
While picking or compiling orders from transporting units, such as e.g. articles or containers, it is necessary to provide the transporting or storage units, which are associated with a common order, in a directed or sorted fashion. In addition, it is conventional to intermediately store (buffer) the transporting units of an order, until all of the transporting units required for the order are present. They are then passed together onto a collecting line which leads them e.g. to the palletization area, picking station, goods issue, shipment etc.
In the picking station the goods for fulfilling an order are taken from the storage units and placed according to the order into an order container etc. The storage container (often called donor) is then routed back into the racking storage and stored until needed for the next order.
A (high bay) racking storage facility includes a storage-entry area, via which the goods are supplied to and from which the Automatic Storage and Retrieval Machine (hereafter called AS/RS) collects the goods for placement in storage, the so-called front-zone. In a similar manner, a retrieval area is required, at which after retrieval from storage the AS/RS deposit the goods which are likewise assigned to the front-zone. In the case of automatic picking storage facilities, picking locations are typically situated nearby the front-zone. In the front-zone, the goods are also identified for the inventory management system or the material flow computer.
EP 1 964 792 B1 for example discloses a method of making transporting units available from a storage facility on at least one collecting line. AS/RS in each storage racking aisle, retrieval-from-storage and outbound lines are controlled, in such a way as to be matched and coordinated to one another, and are loaded with goods that ultimately they end up on, or are discharged from, the collecting line in a sorted fashion.
The control and matching are thus relatively complex and require evident technical work in the so-called front-zone, i.e., the area outside the actual racking, is necessary to achieve high throughput and sequencing.
Further it is difficult to manage fluctuations in demand within storage facilities. Manually run storage facilities with manual picking stations usually capable of managing the fluctuation and have low initial costs and can be very effective for very low volume articles in general and high volume particularly across limited articles and low cost labor situations. However, they must be larger in space to handle the same amount of orders as automated systems. In addition, it is difficult to control the progress of manual operations in the timely fashion.
A high degree of automation works well for a demand at a sustained high level and high labor cost situations. However, if the automated system is maxed out no further increase in capacity is possible. Also some items cannot be automatically handled or picked.
In contrast thereto, embodiments of the present disclosure provide a method of order fulfilling, which provides the possibility of increasing and decreasing capacity so as to handle fluctuations in demand of order fulfillment, as well as addressing other related and unrelated problems in the art.